linux-kernel - [PATCH V4 3/3] i2c: qup: Fix error handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1465582101-19391-4-git-send-email-sricharan@codeaurora.org>
Date:	Fri, 10 Jun 2016 23:38:21 +0530
From:	Sricharan R <sricharan@...eaurora.org>
To:	linux-arm-msm@...r.kernel.org, ntelkar@...eaurora.org,
	galak@...eaurora.org, linux-kernel@...r.kernel.org,
	andy.gross@...aro.org, linux-i2c@...r.kernel.org,
	agross@...eaurora.org, linux-arm-kernel@...ts.infradead.org,
	nkaje@...eaurora.org, absahu@...eaurora.org
Cc:	sricharan@...eaurora.org
Subject: [PATCH V4 3/3] i2c: qup: Fix error handling

Among the bus errors reported from the QUP_MASTER_STATUS register
only NACK is considered and transfer gets suspended, while
other errors are ignored. Correct this and suspend the transfer
for other errors as well. This avoids unnecessary 'timeouts' which
happens when waiting for events that would never happen when there
is already an error condition on the bus. Also the error handling
procedure should be the same for both NACK and other bus errors in
case of dma mode. So correct that as well.

Signed-off-by: Sricharan R <sricharan@...eaurora.org>
---
 drivers/i2c/busses/i2c-qup.c | 76 ++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 35 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index b8116e5..44c80ae 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -310,6 +310,7 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
 	u32 opflags;
 	u32 status;
 	u32 shift = __ffs(op);
+	int ret = 0;
 
 	len *= qup->one_byte_t;
 	/* timeout after a wait of twice the max time */
@@ -321,18 +322,28 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
 
 		if (((opflags & op) >> shift) == val) {
 			if ((op == QUP_OUT_NOT_EMPTY) && qup->is_last) {
-				if (!(status & I2C_STATUS_BUS_ACTIVE))
-					return 0;
+				if (!(status & I2C_STATUS_BUS_ACTIVE)) {
+					ret = 0;
+					goto done;
+				}
 			} else {
-				return 0;
+				ret = 0;
+				goto done;
 			}
 		}
 
-		if (time_after(jiffies, timeout))
-			return -ETIMEDOUT;
-
+		if (time_after(jiffies, timeout)) {
+			ret = -ETIMEDOUT;
+			goto done;
+		}
 		usleep_range(len, len * 2);
 	}
+
+done:
+	if (qup->bus_err || qup->qup_err)
+		ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
+
+	return ret;
 }
 
 static void qup_i2c_set_write_mode_v2(struct qup_i2c_dev *qup,
@@ -793,39 +804,35 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
 	}
 
 	if (ret || qup->bus_err || qup->qup_err) {
-		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
-			msg--;
-			dev_err(qup->dev, "NACK from %x\n", msg->addr);
-			ret = -EIO;
+		if (qup_i2c_change_state(qup, QUP_RUN_STATE)) {
+			dev_err(qup->dev, "change to run state timed out");
+			goto desc_err;
+		}
 
-			if (qup_i2c_change_state(qup, QUP_RUN_STATE)) {
-				dev_err(qup->dev, "change to run state timed out");
-				return ret;
-			}
+		if (rx_nents)
+			writel(QUP_BAM_INPUT_EOT,
+			       qup->base + QUP_OUT_FIFO_BASE);
 
-			if (rx_nents)
-				writel(QUP_BAM_INPUT_EOT,
-				       qup->base + QUP_OUT_FIFO_BASE);
+		writel(QUP_BAM_FLUSH_STOP, qup->base + QUP_OUT_FIFO_BASE);
 
-			writel(QUP_BAM_FLUSH_STOP,
-			       qup->base + QUP_OUT_FIFO_BASE);
+		qup_i2c_flush(qup);
 
-			qup_i2c_flush(qup);
+		/* wait for remaining interrupts to occur */
+		if (!wait_for_completion_timeout(&qup->xfer, HZ))
+			dev_err(qup->dev, "flush timed out\n");
 
-			/* wait for remaining interrupts to occur */
-			if (!wait_for_completion_timeout(&qup->xfer, HZ))
-				dev_err(qup->dev, "flush timed out\n");
+		qup_i2c_rel_dma(qup);
 
-			qup_i2c_rel_dma(qup);
-		}
+		ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
 	}
 
+desc_err:
 	dma_unmap_sg(qup->dev, qup->btx.sg, tx_nents, DMA_TO_DEVICE);
 
 	if (rx_nents)
 		dma_unmap_sg(qup->dev, qup->brx.sg, rx_nents,
 			     DMA_FROM_DEVICE);
-desc_err:
+
 	return ret;
 }
 
@@ -841,9 +848,6 @@ static int qup_i2c_bam_xfer(struct i2c_adapter *adap, struct i2c_msg *msg,
 	if (ret)
 		goto out;
 
-	qup->bus_err = 0;
-	qup->qup_err = 0;
-
 	writel(0, qup->base + QUP_MX_INPUT_CNT);
 	writel(0, qup->base + QUP_MX_OUTPUT_CNT);
 
@@ -881,12 +885,8 @@ static int qup_i2c_wait_for_complete(struct qup_i2c_dev *qup,
 		ret = -ETIMEDOUT;
 	}
 
-	if (qup->bus_err || qup->qup_err) {
-		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
-			dev_err(qup->dev, "NACK from %x\n", msg->addr);
-			ret = -EIO;
-		}
-	}
+	if (qup->bus_err || qup->qup_err)
+		ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
 
 	return ret;
 }
@@ -1178,6 +1178,9 @@ static int qup_i2c_xfer(struct i2c_adapter *adap,
 	if (ret < 0)
 		goto out;
 
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+
 	writel(1, qup->base + QUP_SW_RESET);
 	ret = qup_i2c_poll_state(qup, QUP_RESET_STATE);
 	if (ret)
@@ -1227,6 +1230,9 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
 	struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
 	int ret, len, idx = 0, use_dma = 0;
 
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+
 	ret = pm_runtime_get_sync(qup->dev);
 	if (ret < 0)
 		goto out;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation